Novel Two-Dimensional ABX Dirac Materials: Achieving a High-Speed Strain Sensor via a Self-Doping Effect.

The pristine semimetal property of two-dimensional (2D) Dirac materials has limited their practical applications in today's electronic devices. Here we report a new type of 2D Dirac material, termed ABX (A = F, Cl, Br, or I; B = P or As; X = C or Si) monolayers. We demonstrate that 14 ABX monolayers possess good stability and high Fermi velocities. The FPC, ClPC, BrPC, and FAsC monolayers exhibit a pristine n-type self-doping Dirac cone due to the interactions of electrons between the A-B units and C rings, which is beneficial for realizing high-speed carriers. Interestingly, the ClPSi monolayer exhibits remarkable responses to strain because a self-doping Dirac cone can be induced by relatively small in-plane biaxial strains (-5%), and the current-voltage () curves verified that the response strength is 11.57 times that of the graphene-based strain sensor at a bias of 1.10 V, indicating that the ClPSi monolayer could be used as a potential excellent strain sensor.